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Thread: Query Tuning

  1. #1
    Join Date
    Mar 2004
    Location
    India
    Posts
    87

    Unanswered: Query Tuning

    What is indicated by the following in the explain Plan
    BITMAP CONVERSION FROM INDEX RANGE SCAN
    BITMAP CONVERSION TO ROWID

    Is it possible to include the query explain plan for performance (given below)

    --------------------------------------------------------------------------------
    | Operation | PHV/Object Name | Rows | Bytes| Cost |
    --------------------------------------------------------------------------------
    |UPDATE STATEMENT |----- 2087731899 ----| | | 1688 |
    |UPDATE | | | | |
    | TABLE ACCESS FULL |TCS_MIS_PROJECTED_HD | 584K| 66M| 1688 |
    | SORT AGGREGATE | | 1 | 520 | |
    | HASH JOIN OUTER | | 1 | 520 | 11 |
    | HASH JOIN OUTER | | 1 | 266 | 7 |
    | INDEX RANGE SCAN |TCS_MIS_PROJECTED_HD | 1 | 12 | 3 |
    | VIEW | | 1 | 254 | 3 |
    | SORT GROUP BY | | 1 | 91 | 3 |
    | TABLE ACCESS BY INDEX ROWI|TCS_MIS_BILLING_SPLI | 1 | 91 | 3 |
    | BITMAP CONVERSION TO ROWI| | | | |
    | BITMAP AND | | | | |
    | BITMAP CONVERSION FROM | | | | |
    | INDEX RANGE SCAN |TCS_MIS_BILLING_SPLI | | | 1 |
    | BITMAP CONVERSION FROM | | | | |
    | INDEX RANGE SCAN |TCS_MIS_BILLING_SPLI | | | 7 |
    | VIEW | | 1 | 254 | 3 |
    | SORT GROUP BY | | 1 | 94 | 3 |
    | TABLE ACCESS BY INDEX ROWID|TCS_MIS_BILLING_SPLI | 1 | 94 | 3 |
    | BITMAP CONVERSION TO ROWID| | | | |
    | BITMAP AND | | | | |
    | BITMAP CONVERSION FROM R| | | | |
    | INDEX RANGE SCAN |TCS_MIS_BILLING_SPLI | | | 1 |
    | BITMAP CONVERSION FROM R| | | | |
    | INDEX RANGE SCAN |TCS_MIS_BILLING_SPLI | | | 5 |
    --------------------------------------------------------------------------------

  2. #2
    Join Date
    Sep 2002
    Location
    UK
    Posts
    5,171
    Provided Answers: 1

    Re: Query Tuning

    When you post explain plan output, can you not do it in a way that preserves the formatting of the output? Makes it very hard to read otherwise.

  3. #3
    Join Date
    Sep 2002
    Location
    UK
    Posts
    5,171
    Provided Answers: 1

    Re: Query Tuning

    As I understand it, BITMAP CONVERSION FROM ... takes the output from the preceding step and converts it to bitmap form so that it can be used with a bitmap index. BITMAP CONVERSION TO ROWID is the step that takes a bitmap result and finds the associated ROWIDs so that the records can be selected.

    Someone else may be able to explain better. That is just what I glean from reading the documentation.

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